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Cow Fertility and Effect on Longevity

Cow Fertility and Effect on Longevity. PAUL VANRADEN Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD paul@aipl.arsusda.gov. Fertility / Longevity Data. Cows born 1992-1994 Cows sold for dairy purposes excluded 1,062,791 cows remained

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Cow Fertility and Effect on Longevity

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  1. Cow Fertility and Effect on Longevity PAUL VANRADEN Animal Improvement Programs Laboratory Agricultural Research Service, USDA, Beltsville, MD paul@aipl.arsusda.gov

  2. Fertility / Longevity Data • Cows born 1992-1994 • Cows sold for dairy purposes excluded • 1,062,791 cows remained • Sired by 3080 sires • Progeny tested bulls with > 60 daughters • Older bulls to provide ties and relationships • Multiple-trait REML analysis • Heritabilities and correlations • Highest and lowest PTA’s (for bulls with > 2000 daughters)

  3. Cow Fertility • Days Open • Calving interval – 280 days • Lower limit of 50 days, upper limit 250 • Sold for reproductive problems = 250 • Genetic parameters • 3.7% heritability • .32 correlation with protein • .30 correlation with SCS

  4. Bulls with Low Daughter Fertility

  5. Bulls with High Daughter Fertility

  6. PL and Lifespan Defined • PL • Credit for maximum 10 mo per lactation • Records  305d weren’t stored in database • Long calving intervals unprofitable • Lifespan • Credit for months between lactations • Higher yield and bST allow longer lactations • Embryo donors not penalized

  7. Lifespan and PL Compared • Heritability • 6.7% for lifespan • 7.6% for PL • (8.5% official PL estimate since 1994) • Genetic correlations of lifespan • .986 with PL • More correlated than PL with yield • Less correlated than PL with SCS • Less correlated with fertility (-.46 vs -.59)

  8. Conclusions Cow fertility has low heritability (3.7%) but high genetic correlation with PL (-.59). • Selection on PL is effective, but cow fertility evaluations could increase lifetime profit. • Embryo donors may need special edits or extra credit in longevity and fertility evaluations.

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